Pressure cooker with automatic vent



Oct. 21, 1 952 e. c. WYMAN 2,614,722

PRESSURE COOKER WITH AUTOMATIC VENT Filed May 4, 1948 2 SHEETS-SHEET 1 Oct. 21, 1952 G. c. WYMAN 2,614,722

PRESSURE COOKER WITH AUTOMATIC VENT Filed y 4. 194a GZe Ina/12 1, 71/0. 3346 2 4134 q yljn Patented Oct. 21 1 952 UNITED STATES PATENT OFFICE V i I i I PRESSURE ooioift a zirnno rom Q v Tic EGlennC. WY anLRbm N. assign rito Revere I Copper and Brass Incorporated, Roma-N. Y.,. a corporation of Maryland 1 nppiicauqn nayt, 194s, 'SerialNo. 25, 000

Myinven'tion relates to pressure cookers.-

' Claims. (01, zzoimff The invention has among its objectsa pressure cooker provided with a lock responsive to fluid pressure within the cooker for preventing opening of the-coverwhile the cooker is under pressure, thereby enforcing venting of the cooker by the operator before the cover can be opened. Also among the objectsof the invention 'is theprovision of a signaling dev i-ce fora pressurecooker;

'The'above and other objects of theinvention willr howevenbe best understood from the following. description when read in the light of I the accompanying drawings of a specific embodiment of the invention selected for illustrative purposes, while the scope of the invention will be more particularly pointedou't in the appended claims. 1

g 1 In the drawings:

Fig. 1' is'a plan of a pressure cooker according tothe invention; l 1 Fig. 2 isan elevation of a pressure cooker according-to l, with parts broken away; :Fig.:'3 shows a detail of Fig. '1,- on anenlarged Fig. 4 is a section on the line 4-4 o f-F-ig. 3, this section line being also applied to FigJl for convenience in following thefldrawings; and

Fig.5 is :a section correspondingto Fig. 4, with the parts in a different operative position.

, Referring to the drawings,the pressure cooker illustrated comprises a container,' preferably formed of sheet metal such as stainless steel, having a bottom 1 and. cylindrical side walls 3-. "Ad.-

Qjacenttheirupper edges the side-walls are formed to present an upwardly and outwardly flared frusto-conical portion 5 extending entirely aboutsaid walls. At its upper edget-his f-rusto-conicalport'lonois shown as formed to present an inwardly turned "lip l extending about said portion for approximately 180. At the side of the frustoconical portion. diametrically'opposite the mid portionof the lipil the upper edge of the frustoconical portion is formed with an outwardly projeoti'ng downturned lip 9 of much shorterangular extent than the lip I. Carried by the container is a radially projecting handle H having abase [portion ll-3 secured to the cylindrical wall of :the

container below the lip 9, preferably b welding,

this handle being provided with the handle grips v further illustrated, the cove nlwhich also is preferably formed-of sheet metal suchgas stainless steel, is shaped to :present a dome-dike central portion] I surrounded .by .a flattenedirelatively narrow annular flange-1:9,; integral with out; of? vertical alignmentv conical container portion 5 so a to seal the outer-peripheral edge ofthis flange is'an inwardly and downwardly turned frusto-conical flange 2| extending.: entire1y about I the cover Carriedzbylthe, cover at its under side is a gasket ring 23 of greater height than the flange 2-;I this ring being formfid of flexible material such- -as syntheticrubber, vshaped to fit into-the spaoewbe-v tween the zflanges l9. and 2!; and to provide .a

lower portion 525 whichprojects radially beyond thelouter side of the flange, at. its lower-edge I sojas to bear'iuninterruptedly against the inner wall of the Hfrusto-conical portion 5 59f; the con: taineraywhen the cover is assembled wi-ththe I 1 As shown, the cover is provided withlggmmiiy projecting handle 1 ,2 1- providedwith the handle grips: .2 9. This handle isprovided with a :base

portion :31 3 which conforms. to the upperlside's 10f thezdome-shaped portion 1 land annular E flange l:.9:,s of the cover; .-:-to both .of which i such" base portion is secured preferably by; welding; r se-.-

cured tothe under side of the handle -2,7:,-:preferablyby'welding, is the .base;-'.33 OfLiErgSliIiPfilikG metallic member which; at its. end adjacent ithe "cover, provided with a downtnrned portion 3 5., latter, at-itsdower tend is upwardly turne ft'o-:present.;a hooki3'l. I;

"The ,COVB1' :'iS applied to hepontamerior securing-it thereto-ywith the handle; 2d,;offithe cover ith the handle la of the container and: with 717116;"1 handle -21 :inclined sli htly upward to such {a degree" that the edge lof ltzh e-coverhandle under the :lipll of :the cont'ainer. when the cover is initially pl'aced on the coni-j tainer a clearance exists between the eon-miner lip ET and the cover flange as clearly;- shown by Fig. 4,:and'aclearance betweenthe cotitaine'r ri :Qaridcoverhook' 31, as clearly shown-by F-igi i theseclearances being e ual. Under these 'conditions'the' radially outwardly projecting portion-25 of'the gasket -ring zs bears againsttlrr tebetween the cover-and container fand thus pressure to-l'build np i-n the-cooker; pressure b lc l's'tip the-cover rises so as t 'up' the mentioned clearances; as teams-ted in Fig. 5, the gasket ring due to its resiliency and the pressure in the cooker remaining in contact with the frusto-conical container portion so that at all times the gasket renders the joint between the cover and the container steam-tight.

As shown, the base portion 3| of the cover handle and portions of th cover immediately below it are perforated for receiving a flanged plug 39, preferably formed of yieldable material such as rubber, sprung into such perforation. This plu is formed with a through passage serving as a vent opening 4| for the cooker. Cooperating with the upper end portion of the vent opening is shown a frusto-conical valve 43 carried at the under side of a weight 45, the latter being pivotally secured at 41 to upstanding cars 49 formedat opposite sides of the cover handle 21, With the parts as shown in their full line position in Fig. 2 the swinging weight and valve 43' will control the vent opening 4| to prevent a predetermined maximum pressure in the cooker being exceeded. When the weight is swung to its dotted line position shown by Fig. 2 the vent opening will be maintained in open condition. QDiametrically opposite its handlell the containerlip I is shown as carrying a member presenting on said lip an inwardly extendingprojectionor lip 5| of short angular extent, the-in.- ner'edge of which projection is provided with a notch 53. As shown, this member, which is preferably. formed of sheet metal such as stainless steel, is formed with a base portion shaped to conform to the upper surface of the lip 1, to which latter it is secured preferably by welding.

Diametrically opposite its handle 21 the cover adjacent its annular flange |9thereof is formed with a depressed portion 51 having a'flat bottom 59. This bottom is formed with a perforation 6| which is in vertical alignment with-the notch 53 oftheprojection orlip 5| when the two handles H and 21 are in vertical alignment.' Loosely and reciprocably extending through this perforation is ametal locking pin 63 the lower end of which is shown as integrally formed with a head 65 of larger diameter than the perforation. On its upper side the head carries an annular gasket washer B1 of yieldable material such as synthetic rubber. The upper end of the pin, which projects through the vent opening- BI, is shown as formed with a reduced' diameter portion 69 providing an upwardly facing annular shoulder 1| on the pin. This reduced diameter portion 69 projects through thecentral perforation 13 of a metal head 15, which latter also is of larger diameter than the perforation 6|, the upper end of the reduced diameter portion being riveted over,

.as'indicated at 'I'Lfor securing the head 15 to the its position, shown by Fig. 5, firmly-to seat the gasket washer 61 against the portions of the under side of the cover surrounding the perforation 6| so as to prevent escape of; pressur fluid through such perforation. ;Whenfithe-pin is'so raised it will project into the notch 53-,of the projection or lip 5|, and thus will prevent the cover being rotated .relative to the container for disengaging the above describedmeansior securing the cover to the container until the cove'r'vent is opened for relieving the pressure in the cooker to cause the pin to drop to its position shown by Fig. 4. Preferably, the lateral sides of the head 15 are tapered downward, as indicated at 19, so that the steam escaping through the perforation 6| when the pin begins to lift will, by acting on such tapered sides, rapidly lift the pin from its position shown by Fig. 4 to that shown by Fig. 5, and thus reduce to a minimum the escape of pressure fluid from the cooker while the pin is being lifted.

It will also be observed that the pin 63, which rises when the water in the cooker is at approximately boiling point, also serves as an indicator for showing when the cooker is under pressure and when it is not under pressure. By observing the position of the pin, the head I5 of which is mostly concealed by the walls of the recess 51 and the projection or lip 5| when the cooker is not under pressure and is clearly visible when the cooker is under pressure, the operator will have an indication of when it is safe to releasethe In fact, the member forming the lip 5| may be entirely omitted when it is desired to omitthe feature of locking the cover against rotation, in which case the pin will still serve as an indicator. In such case when the cooker is under pressure and it is desired to remove the cover the operator by use of a suitable instrument, suchas a spoon or knife, may press the pin inward and hold it in such position to cause the valve constituted by the washer 61 to open the vent-passage afforded by the perforation 6|, and as soon as the operator observes that the pin ceases to exert an upward pressure on such instrument and will remain in its lower position when the instrument is removed the operator will know that the cooker is not under pressure and that the cover may be safely released. Also, by visually observing that the pin has dropped when the cooker is vented by opening the weight valve, the operator will know when itis safe to open the cover. 7 y

It will be understood that within the scope of the appended claims wide deviations may be made from the form of the invention described without departing from the spirit of the invenion.

I claim:

I. A pressure cooker comprising a container, 2. cover for'the latter, means for securing the .cover to the container in closed relation'thereto operated into engaged and released positions by rotation of the cover relative to the container, packing means for sealing against escape of pressure fluid from the cooker the joint between the cover and container when the cover is so secured, means for locking the cover against such rotation when the cooker is under pressure comprismg a part carried by-the container in overlying relation-to the upper side of an edge portion of the cover when the cover is so secured to the container, said edge portion of the cover having an opening, a locking pin member received in said opening for vertical reciprocation from a lower position,"in which position such overlying part is out of the path of said member when the cover is rotated, to an upper position in which said partis in such pathto act as a stop for preventing rotation of the-cover to its position which releases the first mentioned means; said mem- -ber.having a portion below the cover adapted'to be exposed to pressure fluid within the cooker for 5 moving said member to and maintaining it in its said upper position when the cooker is under pressure, spaced shoulders carried by the pin above and below the cover for maintaining said ,pin against removal from the cover, the cover having a vent opening normally constituting the sole means of escape of pressure fluid from the cooker when the cover is secured thereto, a safety valve for said vent opening operative to maintain a predetermined pressure within the cooker, which valve is manually'movable to open position for relieving the pressure within the cooker for causing said member to move from its said upper position to its said lower position.

2. A pressure cooker according to claim 1 in which the reciprocatory member received in the opening in the cover is in the form of a pin having, at the upper and under sides of the cover, shoulder portions for retaining it in said opening, the shoulder portion at the under side of the cover being adapted to seat thereon for preventing escape of pressure fluid from the cooker through said opening when the pin is moved to its upper position by such pressure fluid, the pin being movable by gravity from its upper to its lower position when the pressure within the cooker is relieved by the manual opening of the safety valve.

35A pressure cooker according to, claim 1 in which the part carried by the container in overlying relation to the edge portion of the cover operatlvely' has an opening, through which opening the reciprocatory member received in the opening in the cover extends to above'the upper side of said part when said member is in its upper position, said member being withdrawn from said opening to lie wholly below said part when said member is in its lower position, whereby said member serves as an indicator for the pressure condition within the cooker, said memher having shoulder portions at the upper and under sides of the cover for retaining said memher in said opening in the cover, the shoulder portion at the under sideof the cover bein adapted to seat on the cover for preventing escape of pressure fluid through said opening in the cover when said member is moved to its upper position by such pressure fluid.

GLENN C. WYMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Austria Aug. 10, 1903 

